Cerebrovascular disease is usually divided into two types, ischemic cerebrovascular disease and hemorrhagic cerebrovascular disease, with the ischemic cerebrovascular disease being more common and the cerebral infarction accounting for 59.2%-85%. Ischemic cerebrovascular disease comprises 1) the transient ischemic attack (TIA, also known as mini stroke or transitory ischemic attack), which is a dysfunction caused by a transient, ischemic and focal injury to the brain tissue, and is related to cerebral arteriosclerosis in its etiology; 2) cerebral thrombosis, which results from blood clotting in the case of the atherosclerosis, a variety of arteritises, trauma or other physical factors, or local cerebrovascular lesions due to blood diseases; 3) cerebral embolism, caused by embolisms generated from multiple diseases entering the blood and blocking the cerebral vessels.
Many drugs are now available for the treatment of ischemic cerebrovascular disease. The allopathic medicines are primarily the thrombolytic, antiplatelet and anticoagulant drugs, while the traditional Chinese drugs mainly comprise the Huoxue Huayu (promoting blood circulation and removing blood stasis) traditional Chinese drug injections represented by radix salivae miltiorrhizae and panax notogiseng saponins, the Qingre Jiedu, Xingnao Kaiqiao (clearing away heat and toxic substances) traditional Chinese drug injections represented by Xing Nao Jing and Qing Kai Ling and the Yiqi Huoxue Tongluo (supplementing Qi, promoting blood circulation, removing obstruction in collaterals) oral preparations represented by Ren Shen Zai Zao Wan (radix ginseng reconstruction pills) and Hua Tuo Zai Zao Wan (Hua Tuo reconstruction pills). In clinical practice, the allopathic drugs are mainly used in emergency situation and have evident adverse effects while the traditional Chinese medicine injections are not available for long-term use and the Chinese medicine compound have many problems such as uncertain effect, unclear effective components and lack of stable quality control standard.
Dementia is an acquired consistent mentality impairment syndrome induced by organic pathological changes of the cerebrum. A global epidemiological investigation in 2005 showed that there are about 24,000,000 patients with dementia. The annual increment is 4,600,000 patients with one more patient for every 7 seconds and the number is double for every 20 years. In China, as estimated conservatively, the number will increase by 300% annually from 2001 to 2040. It is anticipated that there will be 81,000,000 patients suffering form dementia by 2040. The occurrence rate of dementia increases with the age. The senile dementia is mainly classified into: A. primary degenerative dementia, i.e. Alzheimer's disease (AD); B. vascular dementia (VD); C. mixed dementia (AD combined with VD); D. other types of dementia (Pick's disease and Dementia with Lewy bodies). AD and VD are the two most primary types in senile dementia and account for more than 90% in all dementia patients, with AD being the most common that patients over 65 years old have dementia and the most lethal.
In clinical practice, the drug of first choice for treatment of senile dementia available now is the cholinesterase inhibitors (such as tacrine, donepezil, rivastigmine, galantamine and the like). The diagnosis for the senile dementia in the traditional Chinese medicine comprises all types of AD, VD or the mixed type in allopathic medicine, including all diseases and symptoms related to senile dementia. The traditional Chinese medicine compounds commonly used for treatment of senile dementia comprise Ding Zhi Xiao Wan (radix ginseng, pachyma cocos, acorus calamus and polygala teuofolia), Tiao Xin Fang (prescription for regulating mental activities) (codonopsis pilosula, pachyma cocos, licorice, acorus gramineus soland, polygala teuofolia, etc.), Bu Shen Fang (prescription for tonifying kidney) (asparagus cochinchinesis, ophiopogon japonicus, crude radix rehmanniae, processed radix rehmanniae, fructus corni, etc.), Dang Gui Shao Yao San (radix angelicae sinensis and paeonia lactiflora powder), Huang Lian Jie Du Tang (coptis chinensis toxic materials removing liquid), Gou Teng San (ramulus uncariae cum uncis powder), Yi Gan San, Xiao Chaihu Tang (small radix bupleuri liquid) and Chai Hu Jia Long Gu Mu Li Tang (radix bupleuri, fossilized dragon's bone and oyster liquid). However, in clinical practice, the cholinesterase inhibitors can only improve the cognition disorder and the emotional symptoms, have no significant effects on fundamental pathological changes. They can only delay (for 1 to 2 years) and can not prevent the progress of the disease, i.e. they can only alleviate the symptoms but can not cure the disease. The long-term use may even induce the increase of the synthesis of the cholinesterase. Tacrine is more likely to result in the severe gastrointestinal reaction and liver toxicity. The traditional Chinese medicine compounds have many problems such as unclear effective components, inconvenience for long-term drug use and lack of stable quality control standard.
Therefore, there are obvious limitation and shortcomings in the allopathic drugs and the traditional Chinese medicines are available now for treatment of ischemic cerebrovascular disease and senile dementia, and a demand remains for the development of a type of drug for treatment of ischemic cerebrovascular disease and senile dementia with affirmative and significant effect, the perfect preparation technique and stable drug quality.